JPS6024965A - Manufacturing method of end face type thermal head - Google Patents

Abstract

PURPOSE:To obtain a highly reliable circuit connection by a method wherein a marker to form a resistor conducting electrode pattern by eliminating a pattern displacement with respect to a resistor array, is determined by simultaneous etching of a part of insulating layer on a main plane when forming a resistor film pattern on an end face of the substrate. CONSTITUTION:On an end face 17a of an end face 17 coated with an insulating layer 18 made of a molten glass or the like of which heat conductivity is smaller than that of a base material, an etching preventing layer such as SiC and a resistor film made of TiC-SiO2 or the like are laminated one upon another. Then, by a photoetching process, a resistor film 20 is partially removed as well as a resistor layer 18 on a main plane 17b, a groove to serve as a marker in case of forming an electrode pattern which conducts to a resistor array 20 is formed. Thereafter, an electrode layer 22 made of Cr-Au or the like is formed, and lastly a pattern which conducts to a resistor array 20 is formed by etching after a mask alignment.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method of manufacturing an end-face type thermal head in which a large number of resistors are formed in a row on the end face of a plate-like substrate.

Conventional Structures and Problems As is well known, the thermal recording system is applied to various terminal printers and facsimile machines as a recording system that is easy to maintain. Particularly recently, a transfer thermal recording system has been developed in addition to the conventional color development type thermal recording system, and full-color recording is also possible with this system.

FIG. 1 shows full-color recording using the thermal transfer recording method. In FIG. 1, 1a is an image receiving paper, 1b is a transfer paper, 2 is a paper feed roller, and 3 and 5 are thermal heads. It is formed in the shape of This method will be called a planar thermal head. In the latter thermal head, heat generating parts 5b are formed in a row on one of the four surfaces (end surface) parallel to the thickness direction of the substrate 5a. This method is called an end-face type thermal head.

The 11th ffia is full-color recording using a planar thermal head, and the 10th ffia is full-color recording using an edge-type thermal head.

In FIG. 1, the image receiving paper 1a is wound and fixed around the paper feed roller 2, and in this state, the image receiving paper 1a is pressed against the heat generating parts 3b and 6b of the thermal heads 3 and 5 via the transfer paper 1b, and the image receiving paper 1a is pressed against the roller 2. As the image-receiving paper 1b rotates, the image-receiving paper 1b is sent in the direction of the arrow. For example, cyan, magenta, yellow, and black transfer papers (not shown) are placed on the image receiving paper 1b, with the outer periphery of the paper feed roller 2 as a unit length (uniformly for each color within this unit length range). It is coated. Therefore, each rotation of the paper feed roller produces cyan and magenta.

Color recording can be performed by transferring each color of yellow and black (operation of heating the heat generating parts 3b and 5b according to the image signal).

- In the recording method described in , when using a flat helide, the difference from the end face type is that the heat generating part 3b is formed on the surface where the heat generating part 3b is formed, and the area other than the part where the heat generating part 3b is formed is It is a curse not to come into contact with the transfer paper 1b, the image receiving paper 1a or the roller 2. This limitation poses a major problem with conventional planar heads.

That is, in the conventional planar thermal head, as shown in FIG.
is provided. This cover is provided for the purpose of mechanically protecting the semiconductor elements connected to each heat generating part 3b or the lead wires connected to the electrodes of the heat generating part 3b to facilitate heating of the heat generating part 3b. ing. Further, the length of the outer periphery of the paper feed roller 2 needs to be at least longer than the short side of the recording screen. For this reason, the planar thermal head/lid board 3d must be larger than the conventional single-color recording thermal head/lid board, and as the recording screen becomes larger, the head must also become larger. In addition to greatly increasing the price of the head, the color recording apparatus itself is also large, and the cost involved also increases.

The above is an example of a comparison of the methods of configuring the recording sections of a flat head and an edge head when color recording is performed using a thermal transfer method.

Even from such a simple comparison, the usefulness of the edge-type thermal head in the thermal transfer recording system is clear, and in addition to the above, there are various other points in which the edge-type head is easier to use than the flat-type head. For example, the above-mentioned ability to quickly view the recorded area is one example, and ease of use alone is an example of this. It also has the advantage of being easy to secure. Although there are many other advantages of the end-face type, most conventional heat-sensitive recording systems have been carried out using the flat type. This is because it has been generally believed that planar heads are easier to manufacture than end face heads.

Figures 2 and 3 show a method for manufacturing a flat thermal head. In FIGS. 2 and 3, 6 is a plate-shaped substrate, 6a is an insulating layer,
7 etching prevention layer, 8 resistor film, 9 electrode layer, 1
0 is a heat generating part.

As shown in Figure 2, an electrical insulating layer with a lower thermal conductivity than the prefectural side and an insulating layer 6 of glass etc. are placed on a plate-shaped substrate made of alumina etc.
An etching prevention layer 7 made of SiC or the like and a resistor film 8 are sequentially formed by vapor deposition on the plate-shaped substrate 6 coated with a. The resistor film 8 and the electrode layer 9 are photo-photographed to form a wiring pattern in which a plurality of resistors 8 are arranged.
Parts of the electrode layer 9 and the resistor film 8 are removed by etching, and then masks are aligned so as to cross a part of each resistor film 8 of the wiring pattern in order to form the heat generating part 10. A portion of the upper electrode layer 9 is removed by etching. The order of the formation method shown in FIG. 3 may be reversed. Also, does the insulating layer (glass layer) ea mentioned above have a mirror surface necessary for forming fine patterns? () and are important for increasing thermal efficiency.

On the other hand, the resistor film 8 is required to have high heat resistance pulse characteristics and high resistance, and a resistor material that meets these requirements is a high melting point H material or a combination of a high melting point starch and an oxide or nitride. It is a mixed membrane (thermerite membrane). However, the patterning of the resistor film 8 formed using these A materials is carried out using a mixed solution of hydrofluoric acid and nitric acid;
is also etched. This etching speed is the resistor film 8
faster than

For example, when a Tic-8iO2 thermet film with a thickness of Q1 .mu.m is formed as the resistor film 8, if this film is etched with the above-mentioned etching solution, the glass layer 6a will be etched by about 2 .mu.m at the same time.

If a step is created due to this wide and deep etching, cracks are likely to occur, and the heat pulse resistance characteristics are greatly deteriorated. Moreover, when bonding leads for connection to an external circuit, cracks are likely to occur in the glass layer 6a, resulting in a decrease in reliability.

Furthermore, it is not possible to create a high-density head of 12 heads/mm or more.

In order to prevent these Ω problems, a film 7 made of a material that is not corroded by the above-mentioned elithinda solution is formed below the resistor film to prevent the glass layer 6a from being etched by direct contact with the elytinda solution. It is prevented. The material for this etching prevention film 7 is 5iOz because it is required to have good insulation properties, good adhesion, and be easy to prepare.
and Ta205 are often used.

An end face type thermal head can also be manufactured using the above-described manufacturing method for a flat type thermal head.

Figures 4 and 6 show the manufacturing method. In FIGS. 4 and 5, 11 is a plate-shaped substrate (a: end surface, b: main plane), 12 is an insulating layer, 13 is an etching prevention layer (a: end surface, b: main plane), and 14 is a resistor. The membrane, 16 is an electrode layer, and 16 is a heat generating part.

As shown in FIG. 4, a plate-shaped substrate 11 made of alumina or the like is coated with an electrically insulating layer having a lower thermal conductivity than the base material and an insulating layer 12 made of glass or the like on one end surface 11a and main plane 11b. An etching prevention layer 13b made of SiG or the like is formed on the main plane 11b of the substrate 11. Next, an etching prevention layer 13a made of SiC or the like and a resistor film 14 are sequentially formed on the end surface 11a of the plate-shaped substrate 11 by the same vapor deposition.
After that, the electrode layer 15 made of 0r-Au or the like is formed into at least a plate shape.
(The two main planes of plate 11 (11b and its opposite (61)
) and on the end face 11a on which the resistor film 14 is formed, and then, as shown in FIG. The electrode layer 15 and a portion of the resistor film 14 are removed by photo-etching as shown in FIG.
The mask is aligned so as to cross a part of the resistor film 14, and a part of the electrode layer 16 on the resistor film 14 is removed by etching. The order of formation shown in FIG. 5 may be reversed. In the case of the resistor film 14, which can be used to fabricate an end face type thermal head, the etching prevention layer may be formed only on one surface on the end face 11a. In No. 13, it must be formed on two surfaces, the end surface 11g and the main plane 11b, for the above-mentioned reason. Etching prevention layer 13a on end surface 11a
Although the resistor film 14 and the resistor film 14 can be formed in the same process, the etching prevention layer 13b on the main plane 11b must be formed separately, which increases the cost by one step compared to the planar type.

Purpose of the Invention In view of the above points, the present invention forms an etching prevention layer only on the end surface (one surface), makes the process similar to that of the planar type, and achieves the same high reliability as the planar type in wiring connection. This invention provides a method for manufacturing an end-face type thermal helidene in which masks can be easily aligned on both the end face and the main plane. When coating a resistor film on the end face of a heat-generating substrate and forming a pattern of the resistor film into a predetermined shape by photo-etching, etc., a part of the insulating layer on the main surface is also etched at the same time, and then a part of the insulating layer on the main surface is etched. This is a manufacturing method in which an end-face type thermal hemlock can be easily produced by forming a current-carrying electrode layer and pattern as a marker when forming a current-carrying electrode pattern.

DESCRIPTION OF EMBODIMENTS Hereinafter, the method for manufacturing the end face type thermal hemlock of the present invention will be described in the sixth embodiment.
．． Shown in Figure 7.8. As shown in FIG. 6, an electrically insulating layer having a thermal conductivity lower than that of the base 4'A is formed on one end surface 17a and the entire main plane 17b of the plate-shaped substrate 1 by using an insulating material such as alumina. The insulating layer 18, such as a general melt, is p −1−
1. On the end surface 17a of the plate-like substrate 17, an etching preventive layer 11 made of SiC or the like and a resistor film 20 such as Tie-8i02 are sequentially laminated. Forming a resistor array 1- At the same time, a portion of the resistor film 2001 is removed by etching, photo-etching, and etching, and at the same time, a portion of the insulating layer 18 on the main plane 17b is also etched to remove current to the resistor array 20. A groove is formed to serve as a marker 21 when forming an electrode pattern.

Subsequently, as shown in FIG.
are formed on at least the two main planes of the plate-like substrate 17 and the end face 17a of the resistor array 20, and a pattern for energizing the resistor array 20 is formed based on the marker 21 formed on the aforementioned main plane 1ab. This is a manufacturing method in which masks are aligned on two surfaces, the end surface 17a and the main plane 17b of the surface on which the insulating layer 18 is formed, and a part of the electrode layer 22 is removed by etching.

Effects of the Invention As can be seen from the above description, the method for manufacturing an end face type thermal head of the present invention involves forming the resistor film 20 on the end face 17a, patterning the resistor film 2o, and then forming the electrode layer 22 on the end face 17a. By forming an electrode pattern and then forming an electrode pattern, it is possible to protect the insulating layer 18 on the main plane 17b without forming an etching prevention layer on the main plane 17b. You can get sex. Further, when patterning the resistor film 20, a part of the insulating layer 18 on the main plane 17b is also etched at the same time, and the end surface 17a of the electrode wiring pattern to be formed thereafter is etched.
By using the marker 21 for mask alignment and drying on two surfaces of the main plane 11b, it is possible to easily align the mask on the two surfaces and prevent pattern shift to the resistor array 2o. This prevents wire breakage due to resist pinholes, scratches, etc.

In this way, the manufacturing method of the present invention has excellent effects11)
It is something that can be done.

[Brief explanation of drawings]

Figure 1 is a diagram showing a method for manufacturing a full-color edge-type thermal head using a thermal transfer recording method.
18... Insulating layer, 19... Etching prevention layer, 2°... Resistor film, 21...
Marker, 22... Electrode layer, 23... Heat generating part. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 3 Figure 4 Figure 6 Figure 8? 2

Claims (1)

[Claims] A resistor film formed on the end face of the heating element substrate is formed by forming a layer of an electrically insulating material with a thermal conductivity lower than that of the base material on the end face of the flat plate and the upper plane thereof, and is formed into a predetermined shape by photo-etching. When forming a shiba pattern, a part of the material layer formed on the main plane is also etched at the same time, so that the material layer is used as a marker when forming a pattern of the current-carrying electrode to the resistor film. Head manufacturing method.